Edwin Arlington Robinson`z interest in human beings as subject matter makes him create many characters in his poems. Especially he employs the sonnet to evaluate the individual experience as universal. In this respect, I attempt to examine the characters who are failures in his sonnets in terms of Matthew Arnold`s `criticism of life` to apprehend what the essential aspect of their existence is. Through his vivid character delineation in narrative sonnets such as "Aaron Stark". "Karma", "The Tree in Pamela`s Garden", "The Rat", "Charles Carville`s Eyes", "Inferential", and "Fleming Helphenstine", Robinson shows us how eccentricities of personality make men lonely, isolated, puzzled, and despised by hidden stories, in a friendly or sympathetic way with more or less philosophical commentaries. Also Robinson`s concern for the relations between men and women, especially the struggle of the lonely women against the selfish or disloyal male results in the dramatic portraits of women in his sonnets such as "Ben Trovato", "An Evangelist`s Wife", "The Woman and the Wife", and "The Growth of `Lorraine`". Poetry can interpret moral world. From this viewpoint, Robinson makes us think over the problem of `how to live` and strengthens the sense of life by his powerful character studies and deep concern with inward experience in his poetry.